1. Field of the Invention
The present invention relates to an optical-interference type display panel and a method for making the same, and more particularly to a display panel in which a transparent conductive layer is employed to form connecting pads for connection to a driving circuit of the panel.
2. Description of Related Art
In order to minimize the bulky size of a computer display, the flat display was developed to replace the conventional CRT display. For example, the most well known flat display is the LCD. In recent years, different kinds of LCDs have been developed by display manufacturers. Most of these manufacturers are dedicated as far as possible to reduce the power consumption of the display so that the LCD will become more suitable for portable electronic products such as cell phones, PDAs and E-books.
Inside the LCD device, the back light module consumes the most power of all the elements. To solve the problem, a reflective type panel is developed, which utilizes the external light as the light source to replace the back light module, or to mitigate the using possibility of the back light module.
Whether for the conventional LCD panel or the reflective type panel, a color filtering film and a polarizing film are constructed in the panel so as to display the color images and control the direction of the light. Even though these thin films are pervious to light, a partial amount of light may be blocked or lost while light passes through these films. To overcome the light loss problem, another reflective type panel called optical-interference panel has accordingly been developed. Based on the interference phenomenon caused when light passes through different thin films, the aforementioned optical-interference panel is able to generate the fundamental red, blue and green colors by properly creating the thin film elements. Thus, the panel is able to show color images without the use of said color filter thin film and polarizing thin film, meanwhile the light transmittance of the panel is also improved so the panel is much more suitable to be applied to the portable electronic products.
With reference to FIG. 12, the single pixel structure in the aforementioned optical-interference panel includes a substrate (70) composed of glass or macromolecule material, a first conductive optical film stack (71) and a supporting layer (72) formed on the substrate (70), and a second conductive optical film stack (73)(also called as a mechanical layer) partly covering the adjacent supporting layers (72), whereby a gap is defined between the first and second conductive optical film stack (71, 73).
When supplying an electric field between the two conductive optical film stacks (71, 73) by an external driving circuit (not shown), the second conductive optical film stack (73) will be slightly deformed and becomes closer to the first conductive optical film stack (71). With the different gap distances between the two conductive optical film stacks (71,73), light beams passing through the panel will have different extents of interference, so that the panel is able to show different colors.
As mentioned above, since the electrical connection is necessary between the conductive optical film stacks (71, 73) and the external driving circuit, a plurality of connecting pads (not shown) that connects these conductive optical film stacks (71, 73) is formed on the substrate (70) for connection to the external driving circuit. Generally, these connecting pads are formed by metal wires. However, because the connecting pads are exposed to the air, these metal wires may become gradually oxidized. Thus, the connecting quality and reliability of the connecting pads may be impaired by the oxidization problem.
To mitigate and/or obviate the aforementioned problem, the present invention provides a novel optical-interference type display panel and a method for making the same.